The Jerusalem Post said that to maintain the air force's numerical strength of 460 combat-capable aircraft the Defense Ministry is working on a plan to upgrade the F-15s and Lockheed Martin F-16s it has rather than phase them out.
It would also seek to buy a squadron of used F-15s from the U.S. Air Force "that will serve as a gap-filler for the air force until the JSF arrives," the Post reported.
In August 2010, Defense Minister Ehud Barak signed off a $2.75 billion contract with Lockheed Martin to buy a squadron of stealthy F-35A Lightning II fifth-generation fighters.
Ultimately, Israel wants a fleet of 75 F-35s to maintain its long-held aerial superiority in the Middle East, which rests on access to U.S. technology.
According to Israeli officials, the Defense Ministry had hoped to acquire another 20 F-35s free of charge as part of a deal between Prime Minister Binyamin Netanyahu's right-wing government aimed at salvaging the foundering Israeli-Palestinian peace process.
But that deal, worth around $3 billion, folded when Washington took a package of incentives off the table after Israel refused to halt settlement expansion in the occupied West Bank.
The plan was to phase out the older of the air force's F-15s and F-16s acquired over the last two decades with the acquisition of the F-35s.
Israel has been counting on getting its hands on at least one squadron of the advanced jet as soon as possible, even though the aircraft might not be delivered and operational in time for a possible air assault on Iran.
So if it's seriously thinking of acquiring former U.S. Air Force F-15s, it would seem to be bracing for having to relinquish some measure of its air superiority and its military deterrence power.
The decision to buy the F-35, billed as the greatest jet fighter in the world, has stirred debate within Israel.
Critics are far from convinced that the air force needs to buy, at around $130 million apiece, such an expensive aircraft, that could preclude the acquisition of other weapons systems to meet future threats.
"For many years, preservation of its qualitative advantage has been a main element of Israeli's security concept," said military analyst Yiftah Shapir of the Institute for National Security Studies at Tel Aviv University.
"For this reason alone, it was clear since the beginning of the JSF project that when the time came, Israel would be interested in purchasing the aircraft," he wrote in the Haaretz daily in January.
"But the F-35 will not be the panacea for Israel's security problems," he declared. "Many of its unique capabilities can be achieved even today by existing planes, upgraded with Israeli-made systems."
Shapir was talking about the F-15I and the Lockheed Martin F-16I, which form the backbone of Israel's strategic strike force and were tailored to meet Israeli requirements.
But, he acknowledged that in the final analysis the clincher for the Israelis is that the Americans will allow them to pay for the initial batch of 20 F-35s with U.S. military aid rather than Israeli taxpayers' dollars -- and that Israel's alliance with the United States precludes buying weapon systems elsewhere.
"The choice is not between 'guns or butter,' but between various American-made weapons systems," Shapir observed.
"The requirement to purchase such systems and the strategic relationship with the United States also rule out examining other options, such as purchasing European aircraft, or even Russia's future fifth-generation combat aircraft."
The Pentagon acknowledged in 2010 that JSF project was running two years' behind schedule and was hampered by cost overruns.
Other countries that have committed to buy the F-35, including Turkey and Norway, are reported to have put their planned purchases on hold because of these difficulties.
In recent weeks, the U.S. Air Force and the U.S. Navy, which along with the U.S. Marines will by buying different variants of the F-35, have said they expect the cost of flying and maintaining the JSF will be 25-40 percent more than it is for their current top-line aircraft like the F/A-18.